U.S. Pat. No. 6,433,206 discloses a process for preparing silicon-containing organomercaptans by hydrogenating bis(organyl-silyl) polysulphides using group VIII metal catalysts which must be preserved from poisoning by water, H2S or alcohols. That process has the drawback that the conversion (“g of product silane” per “minute” per “mmol of catalyzing metal”) under energy-sparing conditions is relatively low. The known reaction proceeds with satisfactory conversion only under high pressure and temperature conditions (>100 bar and >180° C.) which are difficult to realise technically, owing to the high load on the material for the plant.
DE 102004043094.2 discloses a process for preparing mercaptoorganyl(alkoxysilanes) that involves hydrogenating bis(alkoxysilylorganyl) polysulphides at temperatures of <190° C. and pressures of <100 bar with hydrogen and a transition metal catalyst and without adding water, alcohol or H2S.
DE 102004043093.4, furthermore, discloses a process for preparing mercaptoorganyl(alkoxysilanes) that involves hydrogenating bis(alkoxysilylorganyl) polysulphides in a solvent with hydrogen and a transition metal catalyst without any alcohols, H2S or water.